Duplex-crank-piston engine



YNo Model.) 2 sheets-sheet 1.

J. DOW.

DUPLEX GEANK EISTON ENGINE.

Patente'd Deo. 2, 1884.

2 Sheets- Sheet- 2.

(No Model.)

J. DOW.

DUPLEX GRANK PISTON ENGINE.

Patented Deo. 2, 1884,

11pm@ N* Z f.

v M A miv ummm wmingwn. D. c.

Nrrnn STATES Plrrinvr` OFFICE.

J OSIAH DOV, OF LOYVELL, MASSACHUSETTS.

DUPLEX-CRANK-PISTON ENGINE.

SPECIFICATION forming part of Letters Patent No. 308,598, dated December2` 1984.

Application filed March 10, 1854. (No model.)

To @ZZ whom t may concern.-

Be it known that I, Josmrr Dow, a citizen of the United States, residingat Lowell, in the county of Middlesex and State of Massachusetts, haveinvented certain new and useful Improvements in Duplex-Crank-PistonEngines; and I do hereby declare that the same are fully described inthe following specilication and illustrated in the accompanyingdrawings.

This invention relates to improvements in dupleX-crank-pistonsteam-engines; and it is carried out. as follows, reference being had tothe accompanying drawings, in Which- Figure l represents a sideelevation of the improved engine. Fig. 2 represents an end View, seenfrom x in Fig. l. Fig. 3 represents a central longitudinal section onthe line A B, shown in Fig. 2. Fig. 4 represents a crosssection on theline C I), shown in Fig. 3. Fig. 5 represents a cross-section on theline E F, shown in Fig. 3. Fig. 6 represents a side elevation 4of one ofthe intermittently rotary valves for admitting steam to the cylinders.Fig. 7 is a section of the same on line G H in Fig. 6. Fig. S representsa detail view of the valveopening mechanism, and Fig. 9 represents asimilar detail view of the valve-closing mechanism. l

Similar letters refer to similar parts wherever they occur on thedifferent parts of the drawings. In the drawings, a is the piston-shaft,to which the duplex-crank pistons are secured. Said-shaft is located insuitable bearings in the ends of the shell or cylinder, hereinafter tobe described, and has attached to it a spurgear, a', that gears into agear, b', of equal diameter and of equal number of teeth, the latterbeing secured to the shaft b, to which the rotary abutinents aresecured.

c is the shell or steam-cylinder cast in one piece with theabutmentchamber c and base c, as shown, and c3 is a division-wall castin one piece with cylinders c c. Said wall c3 is arranged midway betweenthe ends of shell c c, and by its use the said shell is divided in twoequal compartments, U and V, as shown in Fig. 3, each of suchcompartments contain-- ing a rotary piston and correspondingabutment-cylinder.

d represents the head, secured by means of sleeve or bearing a, on shafta, such bearing i having a cap, da, or equivalent device for holdingsleeve a in place. The sleeve c may be made in two semicircular parts orin one single piece, as may be desired.

a3 is a packing surrounding the shaft a at the inner end of bearing orstuflng box: a, in the usual manner, to effect a steam-tight jointbetween the shaft c and its head d, as shown in Fig. 3. In a similarmanner the bracket d supports the bearing b for the shaft b, and isprovided with cup d'l and stuffing b, for the same purpose, as abovedescribed.

To the opposite end of shell c c is secured the head e, in one piecewith which is cast or otherwise secured the outwardly-projectingvalve-chamber e', having a central bearingsleeve, e, provided withstuffing-box c3 and stuiing e* for the piston-shaft c, as shown in Fig.3. In its lower end the head e has an outwardly-projecting bracket, e5,supporting the bearing b* and its cap eG for the abutmentshaft I), inthe same manner as the corresponding bearing in head d, heretoforedescribed.

b is the stuffing for shaft b in the head e, as usual.

On the shaft a, within the compartment U,

is secured the rotary cylinder f, provided with annular tapering groovesat the junction of roo or suitable material, resting in a correspondinggroove in the sides and outer end of said piston, as shown, so as toeffect a steam-tight n parts on cylinder j, with this differencathatjoint between it and the interior of compartment U.

To the shaft Z), directly below the cylinder j', is secured theabutment-cylinder g, which is of exactly the same diameter as thecylinder f, and said cylinders are heldin contact with each other, so asto allow the one to roll on the other with equal surface velocity, andat the same time preventing the steam from escaping between them.Directly opposite the piston f is made on the abutment-cylinder g acurved cut-away portion, g', to permit the piston f "to pass by thecylinder g as they rotate together in opposite directions. The curvatureof the cut-away portion f/ is such as to keep the piston f in immediateContact with it, so as to prevent escape of steam during such passage ofthe said piston.

The cylinder g is provided with webs g3 g3 on the ends of the cut-awayportion g', between which webs the piston f enters during its passageinto said space g', to still further prevent the escape of steam at thispoint.

At the junction of the ends and curved part of abutment cylinder g, Imake tapering grooves, into which are iitted the tapering packings g4g4, made of metal or suitable materials, to effect a tight connectionbetween said cylinder and the interior of the chamber in which itrevolves.

I prefer to make the abutment-cylinder g Skeleton fashion-that is, witha central hub, g5, secured' to shaft b and radial arms g, as shownso asto make it as light as possible.

g" is a semicircular (more or less) space between the exterior ofabutment-cylinder g and interior of abutment-chamber adapted to receivesteam, and thus to equalize the pressure in compartment U, and causingthe cylinders f g to be held in close contact against each other duringtheir rotation, and also to aid in lubricating the saidabutment-cylinder in its motion.

g8 g5 are packing-rods of metal or'other material located incorresponding grooves, g gg,in the upper sides of abutment-chamber,asshown in Figt, such grooves being made deep enough to contain springs,if desired, to hold said packings against the abutment cylinder toeffect a close joint at such place.

Behind the cylinderf is secured to the shaft a the secondary cylinder 7Lconstructed in the same manner as cylinder f, and secured to it in asuitable manner. The cylinder 7L is located in compartment V, and isprovided with tapering packing-rings Zt h', projecting piston 71,,having packing h3 like the corresponding the piston f is located in adiametrically-opposite direction to t-he piston h, as shown in thedrawings, to etfect a perfect balance of said cylinders.

Below the cylinder h. in the corresponding abutment-chamber, is locatedon the shaft b the abutment cylinder Z, of equal diameter with saidcylinder h, and provided with curved cut-away portion fi, webs i i,tapering packings Z* t, central hub, i5, radial arms i,semi circularspace Z7, packings and grooves in a similar and corresponding manner tothose on abutment-cylinder `f/,with this difference, that the cutawayportion z" is located in a diametrically-opposite direction to thecut-away portion g on cylinder g,to effect a perfect balance of saidabutment-cylinders.

e7 is the steam-inlet to the valve-chamber e', as shown in Fig. 3, fromwhich the steam is conducted back of the respective pistons f h, asfollows:

Through the cylinder j' is made two longitudinal conduits, k and'Z, theformer leading to the cylindrical valve Za in cylinder f, and the latterleading to the corresponding cylindrical valve, Z, in cylinder h.

k and Z are the valve-stems, respectively` for the valves 7c and Z, asshown in Figs. 3 and 4.

M is a flanged collar or bearing-piece secured to the outer end ofcylinder f, and adapted to serve as a bearing for the outer ends ofvalve-stems k Z, as shown in Fig. 3.

f* and h* are steam-channels in the respective cylinders f and h,leading from the respective valves 7c and Z directly behind therespective pistons f h, as shown in Fig. 4, by means of which thesteam-pressure is conducted back of the pistons f lfin the respectivecompartments U and V.

The cylindrical steam-valve 7c has three communicating side openings,(more or less,)lt3 k3 k3, with preferably a central core, Zt, forstrengthening it, as shown in Figs. 6 and 7, and the valve-stem k hasattached to its outer end a cam-disk, 7e, which I term the steam-supplyor valve-opening cam,T7 and said cani is provided with threeside-projections, 7c k, one of which is actuated by the projection m onthe stationary ring m, that is secured to the exterior of thevalve-chamber-bearing sleeve e, as shown in Figs. 5 and 8, for each timethat the cylinder f completes its revolution, and thus causes the valveZt' to be turned onesixth of a revolution around its axis to admit steamthrough channel f4. The cam-disk 7c is also provided with three radialprojections, k6 k 7c, and concavo-convex curves connecting saidprojections, as shown in Figs. 5 and 8, adapted to lie in contact withthe ring on, and to retain the valve k in an open position, inconnection with corresponding openingcurves on closing cam-disk, untilacted on by a corresponding cut-off mechanism.

To permit the projections he to pass by the circular ring m at the timeits projection m acts on either of theside projections, ki, I make adepression, m, on the ring m in close proximity to the ring projectionm, as shown in Fig. 8.

The steam cut-0H or valve-closing mechanism is carried out as follows:

On the valve-stem lo, outside of the camdisk 7c", is secured a similarcam-disk, K4, which I term the cut-off cam,77 and said cam is providedwith three side projections, K K5 IOO iol;

IlO

K5, and three radial projections, K6 K6 K, and intermediate concavoconvex surfaces precisely like those described on disk 704, and adaptedto engage with the projection u on the movable ring a, that is looselysupported and made to turn around the bearingsleeve e, as shown in Figs.3 and 9.

n" is a depression on the outside of ring n,

in close proximity to its projection n, for the sainefpurpose asdescribed relative to projection m on ring m-that is, to permit theradial projections K to pass by ring a while the valve is in the act ofbeing turned. The ring a is toothed on'its outer surface, and into it isgeared the worm o, secured to worm-shaft o', located in suitablebea-rings in valve-chamber e', as shown in Figs. 3 and 5.

. To the outer end of worm-shaft o is secured the small bevel-pinion o",that gears into the bevel gear p,secured to shaft p, located in bearings-in the bracket l), secured to valve-chamber e', as shown in Figs. l, 2,and 3.

The shaftp is rotated more or less in either direction to cut off thesteam at any desired part of the stroke, or to maintain any desired anduniform speed of the engine, by the following mechanism:

To the main shaft a is keyed the eccentricblock q, surrounded by theloose ring q', having an upwardly-projecting rod, Q, attached to it, theupper end of which plays loosely in the sleeve r, forming a part of thehub r', loosely supported on shaft p, as shown in Fig. 3. j

' To the hub r is made an upward extension, r, having hinged to itloosely the two pawls fr and r4, as shown in Figs. 2 and 3.

Directly below pawls r3 and r4 is secured on shaft p the spur or pawlgear s.

To the shaft p is hinged loosely the shieldplate t, that overlaps theupper portion of gear s, and may be swung on the said shaft p to theright or left by its connection to any ordinary governor, so as topermit one of the pawls r3 or r* only to engage at one time into theteeth of gear s, as shown in Fig. 2.

t is a downwardly -projecting balanceweight cast onto the lower side ofthe hub on shield-plate t, as shown in Figs. l, 2, and 3, suchbalance-weight being arranged for the purpose of balancing or steadyingthe plate or shield t in its rocking motion on shaft p.

t is a short lever attached or made in one piece with shield t or itshub or balanceweight t, which is to be connected in any suitable mannerto a governor or regulator of any desirable construction, such governorbeing, however, not shown in the drawings. This speed-regulatingmechanism acts as follows: By the eccentric q q', rod g", and sleeve rthe pawls r3 r4 are oscillated on top of gear s continually, the shieldt being, however, during this motion of pawlsa13 r so worked and held inposition by its connection to the governor-lever u that only one pawl atthe time,or neither of then1,acts on the gears, the other one, or both,`sliding looselyon top of shield t, as shown in Fia'. 2, so as to causethe gear s to turn in one direction, according to whether the governorand engine runs above or below its normal speed. As the gear s is turnedit imparts motion to the loose ring a by the connecting mechanism, asdescribed, and said ring is thereby automatically turned around thebearing-sleeve e to cause its projection n to act on the cut-oftl camK4, and its side projections, K5, to turn the cylindrical valve Ztone-sixth ot' a revolution, so as to cut off the supply of steam topiston f at any desired position of its stroke or revolution, as may bedesired. In a similar manner to the valve Zt, the valve Z has attachedto its valvestem Z, on the outer end thereof, the steamsupply cam-diskZ, having side projections, Z5, and radial projections Z, as shown inFigs. 3 and 8. p

To the valve-stein Z" is also secured the corresponding cut-oif cam, L,provided with side projections, L, and radial projections LG, as shownin said Figs. 3 and 9. The valve Z has, like the valve k, -threccommunicating side openings, Z3 Z3 I, to permit the steam to pass fromconduit Z through the valve Z and conduit or channel h into thecompartment V, back of the piston h. rlhe valve Z has, like the valve7c, a central core to strengthen it. f

The valves k and Z are made to rotate intermittently in one and the samedirection by the opening and closing mechanism, as above described.

Y is the exhaust-opening leading from compartlnents U and V. Suchexhaust may be common to both of said compartments, or it may bc dividedin two exitsf-one for each compartment-if so desired.

The operation of this my improved engine is as follows Steam, beingadmitted through steam inlet e7 into valve-chamber c', passes throughsteam-conduits k' and Z to valves Zt' and Z, and out through openings f*It" into the respective compartn'ients U and V and back of pistonsf h.Fig. 4 shows the position of pistonf and its correspondingabutment-cylinder, g, at the time of admitting steam through opening f.The piston h is then diametrically opposite, and may be pressed onwardby live or expanded steam, as may be desired. j

The steam in advance of the respective pistons f h is free to pass outthrough exhaustopening Y. Duri-ng the rotation of pistons f Zt and theirrespective abutment-cylinders g t' the valves k and Z are intermittentlyrotated in a constant direction by the opening and closing rings m andn, their respective projections m and n', and the opening and closingcam-disks on the valve-stems, as hereinabove set forth and described,the whole of the mechanism being balanced properly, so that the enginemay be run at a very quick speed without causing any noise or poundingand with 'a minimum of frietional resistance. The driving-shaft a may besupported outside of the shell or case c c in suitable bearings orpillow-blocks, and be provided with a suit- IOC IIO

able ily or balance wheel in the usual manner,

`such devices being, however, not shown in the drawings.

Having thus fully described the nature, construction, and operation ofmy invention, I wish to secure by Letters Patent and claiml. In asteam-engine, the shell c c', heads d e, the shafts a b, equally gearedtogether, iu combination with diametrically-opposed cylinders andpistons ff h h, and their respective diametrically-opposed abutments gi, the steam-chest e at the outer end of head e, into which the steam isadmitted through the steam-supply pipe situated upon and through thesaid steam-chest e', as described.

2. In a steam-engine, the rotary cylinder f and its piston f, combinedwith abutmentcylinder g, of equal diameter with cylinder f, the cut-awayportion g', to permit passage of piston f, and curved steam-space gl onthe interior of abutment-chamber, into which the steam passes from themain cylinder for the purpose of pressing the abutment-cylinder gagainst and securing perfect contact with the rotary cylinder f, asdescribed.

3. In a steam-engine, the rotary cylinder f and its piston f, incombination with an abutment-cylinder of equal dia-meter, made skeletonfashion, with hub g5, arms g, side Webs, g3 g3, and having cutawayportion g, substantially as described.

4. In a steam-engine, a rotary cylinder having arrangedwithin itacylindrical valve, k, with side openings, 76315576, adapted to rotateina continuous intermittent direction around its axis, to'deliver andcut off thc supply of steam, as set forth.

5. In a steam-engine, the rotary cylinderf, having arranged within itthe cylindrical valve 7c, in combination with valve-opening cam k",secured to valve-stein k, and provided with side projections, k, andradial projections la, to operate with stationary ring fm, itsprojection m', and recess m, for the purpose of automatically openingthe said valve 7c, as set forth.

6. In a steam-engine, the rotary cylinder f, having arranged Within itthe cylindrical valve 7c, upon the stem 7c of which is arranged thesteam-cutoff cam-disk Kt, having side projections, K5, and radialprojections K6, in combination with the adjustable ring a, itsprojection a, and recess a, for the purpose of automatically closingsaid valve k, as set forth and described.

7. In a steam-engine, the stea1ncut-off mechanism, as described,consisting of eccentrics q, its ring q, and rod q, rocking piece r r,with its sleeve i', the hinged pawls r3 r, shield-plate t, connected tothe governor, and provided with a counter-balance, t', the gear s,secured to shaft p, the bearing-bracket P, and intermediate `connectingmechanism, substantially as described, from shaft p to the loose ring a,as and for the purpose set forth.

`8. In a steam-engine, the rotary cylinder f, V

having a steam passage or passages .7c,located between the axis andouter periphery of said cylinder and communicating with the steampassagef, located behind the piston f, as set forth and described.

9. In a steam-engine, the movable ring or collar n, geared to theWornrshaft o, for the purpose of adjusting the point of cut-off by theaction of the governor, as set forth and described.

In testimony whereof I have affixed my signature in presence of twowitnesses.

JOSIAH DOW.

Witnesses: j

ALBAN ANDRN, HENRY CHADBoURN.

